Digital set-back programmable thermostats typically use a small screen, such as a liquid-crystal display (“LCD”) to display both operational functions and programming values. The user enters commands into the thermostat, such as for setting the current time and date and programming the thermostat, by pressing keys. The keys are often fairly small and are labeled with small type. In many cases a set of instructions explaining the steps that must be taken to operate the thermostat is printed on the thermostat or separately documented, as programming such a thermostat can be quite confusing and tedious. Although programmable thermostats hold out the promise of reducing the energy used by heating systems, the U.S. Environmental Protection Agency, which provides the ENERGY STAR certification for appliances and other devices, has expressed concern that potential energy savings are not being realized because of the difficulties consumers face trying to program conventional digital thermostats.
It is desirable to provide a digital programmable thermostat with a more convenient and intuitive programming and control interface that facilitates use of the thermostat features, particularly features that can result in energy conservation.